Rate and Extent of Reactions - Chemistry

Heat of reaction (△H)

The energy absorbed or released per mole in a chemical reaction.

Endothermic reaction

Energy is absorbed during the reaction. △H > 0.

Exothermic reaction

Energy is released during the reaction. △H < 0.

Activation energy

Minimum energy needed for a reaction to take place.

Activated complex

Unstable transition state from reactants to products in a chemical reaction.

Reaction rate

Change in concentration of reactants or products per unit time.

Collision theory

Model that explains reaction rate as the result of particles colliding with a certain minimum energy.

Positive catalyst

Substance that increases the rate of a chemical reaction without itself undergoing a permanent change.

Ineffective collision

A collision between reactant particles that does not result in a chemical reaction

Effective collision

A collision between reactant particles that does result in a chemical reaction

Boyle’s Law

states that for a fixed mass of an enclosed gas at constant temperature, the pressure is inversely proportional to its volume.